1. Field of the Invention
The present invention relates to an apparatus and method for adjusting the reproduction speed of an optical disk, and more particularly, to an apparatus and method for adjusting the reproduction speed of an optical disk which is capable of selectively adjusting the reproduction speed to a lower speed in advance only with respect to an abnormal regional section of the optical disk inserted into a driver, and normally reproducing a recording signal on-the optical disk at the original high speed with respect to sections excepting for the abnormal regional section.
2. Description of the Background Art
FIG. 1 is a view illustrating the construction of a part of an optical disk reproducing apparatus according to the conventional art. The operation thereof will now be explained with reference to FIG. 2.
FIG. 2 is a graph illustrating the change in running RPM according to an abnormal region of an optical disk.
First, when an optical disk is inserted into a driver, a control unit 16 applies a driving voltage corresponding to a reproduction speed appropriate for the optical disk to a spindle motor M2 through a server 14 and a drive 13, thereby driving the optical disk 10.
Afterwards, a pickup unit 11 outputs a high-frequency reproduction signal reproduced after reading out data from the driven optical disk 10 to a R/F unit 12. The R/F unit 12 performs wave-filtering of the high-frequency reproduction signal, and thereafter outputs the same to a digital signal processing unit 15.
The digital signal processing unit 15 restores the wave filtered signal to a digital bit stream, and thereafter outputs a digital data converted by EFM (Eight to Fourteen Modulation).
Here, when the digital signal processing unit 15 detects an error of data due to drop-out in the above step of restoring the wave filtered signal to a digital bit stream, it produces a specific signal to apply the same to the control unit 16.
Afterwards, an EFM inverter 17 inverts a digital symbol data in unit of 14 bits converted by the EFM to a 8-bit symbol data expected to correspond thereto for thereby outputting the same. At this time, the EFM inverter 17 converts the above data based on EFM table.
Next when the control unit 16 receives a specific signal representing a reproduction error from the digital signal processing unit 15, it controls a CIRC (Cross Interleave Reed-Solomon Code) decoder 18 to execute the process of restoring a reproduced data with an error to a normal data by previously correcting the error of a digital data inputted after being demodulated by the EFM within a predetermined number of times.
Here, in the case that an error data is not restored to the original normal data even if the process of correcting an error is executed within the predetermined number of times, the control unit 16 judges the current reproduction region on the optical disk 10 to be an abnormal region due to scratch, and adjusts the reproduction speed of the optical disk 10 to a lower speed by variably adjusting the driving voltage applied to the spindle motor M2 through the driver 13.
Thereafter, the control unit 16 executes again the process of correcting an error by reading out again a recording data on a corresponding position from the optical disk 10 driven at the lower speed.
In addition, the control unit 16 readjusts the reproduction speed of the optical disk 10 to the higher speed prior to being adjusted to the lower speed within a predetermined time, in a state that the optical disk 10 is driven at the lower speed, and then executes the process of reproducing data.
Here, if an abnormal region is detected from the optical disk 10 a number of times as in FIG. 2 during the execution of the reproduction, and the number of times is more than a predetermined number of times, the control unit 16 fixes the reproduction speed of the optical disk 10 at a low speed, and drives the optical disk 10 at a predetermined low speed until the completion of the reproduction.
However, in the optical disk reproducing method of the conventional art, in the-case that an error data generated when data is reproduced after being read out from the optical disk is not restored to a normal data even if the process of correcting an error is executed as much as a predetermined number of times, since the reproduction speed of the optical disk is gradually adjusted to a lower speed at a corresponding position, there is a problem that the reproduction time is delayed when the optical disk is reproduced.
Accordingly, it is an object of the present invention to provide an apparatus and method for adjusting the reproduction speed of an optical disk capable of selectively adjusting the reproduction speed to a lower speed in advance only with respect to an abnormal regional section of the optical disk inserted into a driver, and normally reproducing a recording signal on the optical disk at the original high speed with respect to sections excepting for the abnormal regional section.
To achieve the above object, there is provided an apparatus for adjusting the reproduction speed of an optical disk according to the present invention which includes: a driving unit for driving the optical disk; a pickup unit for detecting a reproduction signal from data recorded on the optical disk; a signal processing unit for processing the detected reproduction signal; and a control unit for gradually down-adjusting the reproduction speed of an abnormal section from the position at which a reproduction error signal is generated to the position at which the reproduction error signal is not generated, when the reproduction error signal is generated to the above reproduction signal.
To achieve the above object, there is provided a method for adjusting the reproduction speed of an optical disk according to the present invention which includes the steps of: judging if a reproduction error signal is generated from a signal reproduced from the optical disk; adjusting the reproduction speed of the optical disk from the position at which the reproduction error signal is generated; and consecutively storing the reproduction speed of an abnormal section from the position at which the reproduction error signal is generated to the position at which the reproduction error signal is not generated and the range of the value of the reproduction speed varied in the abnormal section.
To achieve the above object, there is provided a method for adjusting the reproduction speed of an optical disk according to the present invention which includes the steps of: judging if the reproduction position generated from the optical disk corresponds to an abnormal section; adjusting the reproduction speed of the optical disk to a lower speed according to the range of the value of the reproduction speed of the optical disk wherein the reproduction position of the optical disk corresponds to the abnormal section; and adjusting the reproduction speed of the optical disk to a higher speed, if the reproduction speed of the optical disk does not correspond to the abnormal section.
To achieve the above object, there is provided a method for adjusting the reproduction speed of an optical disk according to the present invention which includes the steps of: judging if there is an abnormal region on the optical disk by a reproduction signal reproduced after a recording signal is read out from the optical disk; and consecutively storing information on the reproduction speed appropriate for the abnormal region and the position of the abnormal region, if the abnormal region is occurred on the optical disk in the above judging step.
To achieve the object, there is provided another method for adjusting the reproduction speed of an optical disk according to the present invention which includes the steps of: reading out information on the abnormal regional section of the optical disk and the corresponding reproduction speed, and thereafter checking if the current position of the optical disk is included in the read-out abnormal regional section; and variably adjusting the reproduction speed of the optical disk to a reproduction speed corresponding to the abnormal region.